/*
 * Copyright (c) 2012, Thingsquare, http://www.thingsquare.com/.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include "net/uip-ds6.h"
#include "net/uip.h"

#include "lib/list.h"
#include "lib/memb.h"
#include "net/nbr-table.h"

#if UIP_CONF_IPV6

#include <string.h>

/* The nbr_routes holds a neighbor table to be able to maintain
   information about what routes go through what neighbor. This
   neighbor table is registered with the central nbr-table repository
   so that it will be maintained along with the rest of the neighbor
   tables in the system. */
NBR_TABLE(struct uip_ds6_route_neighbor_routes, nbr_routes);

/* Each route is repressented by a uip_ds6_route_t structure and
   memory for each route is allocated from the routememb memory
   block. These routes are maintained on lists of route entries that
   are attached to each neighbor, via the nbr_routes neighbor
   table. */
MEMB(routememb, uip_ds6_route_t, UIP_DS6_ROUTE_NB);

/* Default routes are held on the defaultrouterlist and their
   structures are allocated from the defaultroutermemb memory block.*/
LIST(defaultrouterlist);
MEMB(defaultroutermemb, uip_ds6_defrt_t, UIP_DS6_DEFRT_NB);

#if UIP_DS6_NOTIFICATIONS
LIST(notificationlist);
#endif

static int num_routes = 0;

#undef DEBUG
#define DEBUG DEBUG_NONE
#include "net/uip-debug.h"

static void rm_routelist_callback(nbr_table_item_t *ptr);
/*---------------------------------------------------------------------------*/
#if DEBUG != DEBUG_NONE
static void
assert_nbr_routes_list_sane(void)
{
  uip_ds6_route_t *r;
  int count;

  /* Check if the route list has an infinite loop. */
  for(r = uip_ds6_route_head(),
        count = 0;
      r != NULL &&
        count < UIP_DS6_ROUTE_NB;
      r = uip_ds6_route_next(r),
        count++);

  if(count >= UIP_DS6_ROUTE_NB) {
    printf("uip-ds6-route.c: assert_nbr_routes_list_sane route list is in infinite loop\n");
  }

  /* Make sure that the route list has as many entries as the
     num_routes vairable. */
  if(count < num_routes) {
    printf("uip-ds6-route.c: assert_nbr_routes_list_sane too few entries on route list: should be %d, is %d, max %d\n",
           num_routes, count, UIP_CONF_MAX_ROUTES);
  }
}
#endif /* DEBUG != DEBUG_NONE */
/*---------------------------------------------------------------------------*/
#if UIP_DS6_NOTIFICATIONS
static void
call_route_callback(int event, uip_ipaddr_t *route,
		    uip_ipaddr_t *nexthop)
{
  int num;
  struct uip_ds6_notification *n;
  for(n = list_head(notificationlist);
      n != NULL;
      n = list_item_next(n)) {
    if(event == UIP_DS6_NOTIFICATION_DEFRT_ADD ||
       event == UIP_DS6_NOTIFICATION_DEFRT_RM) {
      num = list_length(defaultrouterlist);
    } else {
      num = num_routes;
    }
    n->callback(event, route, nexthop, num);
  }
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_notification_add(struct uip_ds6_notification *n,
			 uip_ds6_notification_callback c)
{
  if(n != NULL && c != NULL) {
    n->callback = c;
    list_add(notificationlist, n);
  }
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_notification_rm(struct uip_ds6_notification *n)
{
  list_remove(notificationlist, n);
}
#endif
/*---------------------------------------------------------------------------*/
void
uip_ds6_route_init(void)
{
  memb_init(&routememb);
  nbr_table_register(nbr_routes,
                     (nbr_table_callback *)rm_routelist_callback);

  memb_init(&defaultroutermemb);
  list_init(defaultrouterlist);

#if UIP_DS6_NOTIFICATIONS
  list_init(notificationlist);
#endif
}
/*---------------------------------------------------------------------------*/
static uip_lladdr_t *
uip_ds6_route_nexthop_lladdr(uip_ds6_route_t *route)
{
  if(route != NULL) {
    return (uip_lladdr_t *)nbr_table_get_lladdr(nbr_routes, route->routes);
  } else {
    return NULL;
  }
}
/*---------------------------------------------------------------------------*/
uip_ipaddr_t *
uip_ds6_route_nexthop(uip_ds6_route_t *route)
{
  if(route != NULL) {
    return uip_ds6_nbr_ipaddr_from_lladdr(uip_ds6_route_nexthop_lladdr(route));
  } else {
    return NULL;
  }
}
/*---------------------------------------------------------------------------*/
uip_ds6_route_t *
uip_ds6_route_head(void)
{
  struct uip_ds6_route_neighbor_routes *routes;

  routes = (struct uip_ds6_route_neighbor_routes *)nbr_table_head(nbr_routes);
  if(routes != NULL) {
    if(list_head(routes->route_list) == NULL) {
      PRINTF("uip_ds6_route_head lead_head(nbr_route_list) is NULL\n");
    }
    return list_head(routes->route_list);
  } else {
    return NULL;
  }
}
/*---------------------------------------------------------------------------*/
uip_ds6_route_t *
uip_ds6_route_next(uip_ds6_route_t *r)
{
  if(r != NULL) {
    uip_ds6_route_t *n = list_item_next(r);
    if(n != NULL) {
      return n;
    } else {
      struct uip_ds6_route_neighbor_routes *routes;
      routes = (struct uip_ds6_route_neighbor_routes *)
        nbr_table_next(nbr_routes, r->routes);
      if(routes != NULL) {
        return list_head(routes->route_list);
      }
    }
  }

  return NULL;
}
/*---------------------------------------------------------------------------*/
int
uip_ds6_route_num_routes(void)
{
  return num_routes;
}
/*---------------------------------------------------------------------------*/
uip_ds6_route_t *
uip_ds6_route_lookup(uip_ipaddr_t *addr)
{
  uip_ds6_route_t *r;
  uip_ds6_route_t *found_route;
  uint8_t longestmatch;

  PRINTF("uip-ds6-route: Looking up route for ");
  PRINT6ADDR(addr);
  PRINTF("\n");


  found_route = NULL;
  longestmatch = 0;
  for(r = uip_ds6_route_head();
      r != NULL;
      r = uip_ds6_route_next(r)) {
    if(r->length >= longestmatch &&
       uip_ipaddr_prefixcmp(addr, &r->ipaddr, r->length)) {
      longestmatch = r->length;
      found_route = r;
    }
  }

  if(found_route != NULL) {
    PRINTF("uip-ds6-route: Found route: ");
    PRINT6ADDR(addr);
    PRINTF(" via ");
    PRINT6ADDR(uip_ds6_route_nexthop(found_route));
    PRINTF("\n");
  } else {
    PRINTF("uip-ds6-route: No route found\n");
  }

  return found_route;
}
/*---------------------------------------------------------------------------*/
uip_ds6_route_t *
uip_ds6_route_add(uip_ipaddr_t *ipaddr, uint8_t length,
		  uip_ipaddr_t *nexthop)
{
  uip_ds6_route_t *r;

#if DEBUG != DEBUG_NONE
  assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */

  /* Get link-layer address of next hop, make sure it is in neighbor table */
  uip_lladdr_t *nexthop_lladdr = uip_ds6_nbr_lladdr_from_ipaddr(nexthop);
  if(nexthop_lladdr == NULL) {
    PRINTF("uip_ds6_route_add: neighbor link-local address unknown ");
    PRINT6ADDR(ipaddr);
    PRINTF("\n");
    return NULL;
  }

  /* First make sure that we don't add a route twice. If we find an
     existing route for our destination, we'll just update the old
     one. */
  r = uip_ds6_route_lookup(ipaddr);
  if(r != NULL) {
    PRINTF("uip_ds6_route_add: old route already found, updating this one instead: ");
    PRINT6ADDR(ipaddr);
    PRINTF("\n");
  } else {
    struct uip_ds6_route_neighbor_routes *routes;
    /* If there is no routing entry, create one */

    /* Every neighbor on our neighbor table holds a struct
       uip_ds6_route_neighbor_routes which holds a list of routes that
       go through the neighbor. We add our route entry to this list.

       We first check to see if we already have this neighbor in our
       nbr_route table. If so, the neighbor already has a route entry
       list.
    */
    routes = nbr_table_get_from_lladdr(nbr_routes,
                                       (rimeaddr_t *)nexthop_lladdr);

    if(routes == NULL) {
      /* If the neighbor did not have an entry in our neighbor table,
         we create one. The nbr_table_add_lladdr() function returns a
         pointer to a pointer that we may use for our own purposes. We
         initialize this pointer with the list of routing entries that
         are attached to this neighbor. */
      routes = nbr_table_add_lladdr(nbr_routes,
                                    (rimeaddr_t *)nexthop_lladdr);
      if(routes == NULL) {
        PRINTF("uip_ds6_route_add: could not allocate a neighbor table entri for new route to ");
        PRINT6ADDR(ipaddr);
        PRINTF(", dropping it\n");
        return NULL;
      }
      LIST_STRUCT_INIT(routes, route_list);
    }

    /* Allocate a routing entry and populate it. */
    r = memb_alloc(&routememb);

    if(r == NULL) {
      PRINTF("uip_ds6_route_add: could not allocate memory for new route to ");
      PRINT6ADDR(ipaddr);
      PRINTF(", dropping it\n");
      return NULL;
    }


    /* Add the route to this neighbor */
    list_add(routes->route_list, r);
    num_routes++;

    PRINTF("uip_ds6_route_add num %d\n", num_routes);
    r->routes = routes;
  }

  uip_ipaddr_copy(&(r->ipaddr), ipaddr);
  r->length = length;

#ifdef UIP_DS6_ROUTE_STATE_TYPE
  memset(&r->state, 0, sizeof(UIP_DS6_ROUTE_STATE_TYPE));
#endif

  PRINTF("uip_ds6_route_add: adding route: ");
  PRINT6ADDR(ipaddr);
  PRINTF(" via ");
  PRINT6ADDR(nexthop);
  PRINTF("\n");
  ANNOTATE("#L %u 1;blue\n", nexthop->u8[sizeof(uip_ipaddr_t) - 1]);

#if UIP_DS6_NOTIFICATIONS
  call_route_callback(UIP_DS6_NOTIFICATION_ROUTE_ADD, ipaddr, nexthop);
#endif

#if DEBUG != DEBUG_NONE
  assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
  return r;
}

/*---------------------------------------------------------------------------*/
void
uip_ds6_route_rm(uip_ds6_route_t *route)
{
#if DEBUG != DEBUG_NONE
  assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
  if(route != NULL && route->routes != NULL) {

    PRINTF("uip_ds6_route_rm: removing route: ");
    PRINT6ADDR(&route->ipaddr);
    PRINTF("\n");

    list_remove(route->routes->route_list, route);
    if(list_head(route->routes->route_list) == NULL) {
      /* If this was the only route using this neighbor, remove the
         neibhor from the table */
      PRINTF("uip_ds6_route_rm: removing neighbor too\n");
      nbr_table_remove(nbr_routes, route->routes->route_list);
    }
    memb_free(&routememb, route);

    num_routes--;

    PRINTF("uip_ds6_route_rm num %d\n", num_routes);

#if UIP_DS6_NOTIFICATIONS
    call_route_callback(UIP_DS6_NOTIFICATION_ROUTE_RM,
        &route->ipaddr, uip_ds6_route_nexthop(route));
#endif
#if 0 //(DEBUG & DEBUG_ANNOTATE) == DEBUG_ANNOTATE
    /* we need to check if this was the last route towards "nexthop" */
    /* if so - remove that link (annotation) */
    uip_ds6_route_t *r;
    for(r = uip_ds6_route_head();
        r != NULL;
        r = uip_ds6_route_next(r)) {
      uip_ipaddr_t *nextr, *nextroute;
      nextr = uip_ds6_route_nexthop(r);
      nextroute = uip_ds6_route_nexthop(route);
      if(nextr != NULL &&
         nextroute != NULL &&
         uip_ipaddr_cmp(nextr, nextroute)) {
        /* we found another link using the specific nexthop, so keep the #L */
        return;
      }
    }
    ANNOTATE("#L %u 0\n", uip_ds6_route_nexthop(route)->u8[sizeof(uip_ipaddr_t) - 1]);
#endif
  }

#if DEBUG != DEBUG_NONE
  assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
  return;
}
/*---------------------------------------------------------------------------*/
static void
rm_routelist(struct uip_ds6_route_neighbor_routes *routes)
{
#if DEBUG != DEBUG_NONE
  assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
  PRINTF("uip_ds6_route_rm_routelist\n");
  if(routes != NULL && routes->route_list != NULL) {
    uip_ds6_route_t *r;
    r = list_head(routes->route_list);
    while(r != NULL) {
      uip_ds6_route_rm(r);
      r = list_head(routes->route_list);
    }
    nbr_table_remove(nbr_routes, routes);
  }
#if DEBUG != DEBUG_NONE
  assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */
}
/*---------------------------------------------------------------------------*/
static void
rm_routelist_callback(nbr_table_item_t *ptr)
{
  rm_routelist((struct uip_ds6_route_neighbor_routes *)ptr);
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_route_rm_by_nexthop(uip_ipaddr_t *nexthop)
{
  /* Get routing entry list of this neighbor */
  uip_lladdr_t *nexthop_lladdr;
  struct uip_ds6_route_neighbor_routes *routes;

  nexthop_lladdr = uip_ds6_nbr_lladdr_from_ipaddr(nexthop);
  routes = nbr_table_get_from_lladdr(nbr_routes,
                                     (rimeaddr_t *)nexthop_lladdr);
  rm_routelist(routes);
}
/*---------------------------------------------------------------------------*/
uip_ds6_defrt_t *
uip_ds6_defrt_add(uip_ipaddr_t *ipaddr, unsigned long interval)
{
  uip_ds6_defrt_t *d;

#if DEBUG != DEBUG_NONE
  assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */

  PRINTF("uip_ds6_defrt_add\n");
  d = uip_ds6_defrt_lookup(ipaddr);
  if(d == NULL) {
    d = memb_alloc(&defaultroutermemb);
    if(d == NULL) {
      PRINTF("uip_ds6_defrt_add: could not add default route to ");
      PRINT6ADDR(ipaddr);
      PRINTF(", out of memory\n");
      return NULL;
    } else {
      PRINTF("uip_ds6_defrt_add: adding default route to ");
      PRINT6ADDR(ipaddr);
      PRINTF("\n");
    }

    list_push(defaultrouterlist, d);
  }

  uip_ipaddr_copy(&d->ipaddr, ipaddr);
  if(interval != 0) {
    stimer_set(&d->lifetime, interval);
    d->isinfinite = 0;
  } else {
    d->isinfinite = 1;
  }

  ANNOTATE("#L %u 1\n", ipaddr->u8[sizeof(uip_ipaddr_t) - 1]);

#if UIP_DS6_NOTIFICATIONS
  call_route_callback(UIP_DS6_NOTIFICATION_DEFRT_ADD, ipaddr, ipaddr);
#endif

#if DEBUG != DEBUG_NONE
  assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */

  return d;
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_defrt_rm(uip_ds6_defrt_t *defrt)
{
  uip_ds6_defrt_t *d;

#if DEBUG != DEBUG_NONE
  assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */

  /* Make sure that the defrt is in the list before we remove it. */
  for(d = list_head(defaultrouterlist);
      d != NULL;
      d = list_item_next(d)) {
    if(d == defrt) {
      PRINTF("Removing default route\n");
      list_remove(defaultrouterlist, defrt);
      memb_free(&defaultroutermemb, defrt);
      ANNOTATE("#L %u 0\n", defrt->ipaddr.u8[sizeof(uip_ipaddr_t) - 1]);
#if UIP_DS6_NOTIFICATIONS
      call_route_callback(UIP_DS6_NOTIFICATION_DEFRT_RM,
			  &defrt->ipaddr, &defrt->ipaddr);
#endif
      return;
    }
  }
#if DEBUG != DEBUG_NONE
  assert_nbr_routes_list_sane();
#endif /* DEBUG != DEBUG_NONE */

}
/*---------------------------------------------------------------------------*/
uip_ds6_defrt_t *
uip_ds6_defrt_lookup(uip_ipaddr_t *ipaddr)
{
  uip_ds6_defrt_t *d;
  for(d = list_head(defaultrouterlist);
      d != NULL;
      d = list_item_next(d)) {
    if(uip_ipaddr_cmp(&d->ipaddr, ipaddr)) {
      return d;
    }
  }
  return NULL;
}
/*---------------------------------------------------------------------------*/
uip_ipaddr_t *
uip_ds6_defrt_choose(void)
{
  uip_ds6_defrt_t *d;
  uip_ds6_nbr_t *bestnbr;
  uip_ipaddr_t *addr;

  addr = NULL;
  for(d = list_head(defaultrouterlist);
      d != NULL;
      d = list_item_next(d)) {
    PRINTF("Defrt, IP address ");
    PRINT6ADDR(&d->ipaddr);
    PRINTF("\n");
    bestnbr = uip_ds6_nbr_lookup(&d->ipaddr);
    if(bestnbr != NULL && bestnbr->state != NBR_INCOMPLETE) {
      PRINTF("Defrt found, IP address ");
      PRINT6ADDR(&d->ipaddr);
      PRINTF("\n");
      return &d->ipaddr;
    } else {
      addr = &d->ipaddr;
      PRINTF("Defrt INCOMPLETE found, IP address ");
      PRINT6ADDR(&d->ipaddr);
      PRINTF("\n");
    }
  }
  return addr;
}
/*---------------------------------------------------------------------------*/
void
uip_ds6_defrt_periodic(void)
{
  uip_ds6_defrt_t *d;
  d = list_head(defaultrouterlist);
  while(d != NULL) {
    if(!d->isinfinite &&
       stimer_expired(&d->lifetime)) {
      PRINTF("uip_ds6_defrt_periodic: defrt lifetime expired\n");
      uip_ds6_defrt_rm(d);
      d = list_head(defaultrouterlist);
    } else {
      d = list_item_next(d);
    }
  }
}
/*---------------------------------------------------------------------------*/

#endif /* UIP_CONF_IPV6 */
